Safety valve for boiling vessels



June 23, 1931. J 'PFQTZER 1,811,151

SAFETY VALVE FOR BOILING VESSELS Filed Feb. 12, 1930 I 2 Sheets-Sheet l Lfw m I /n venfor':

June 23, 1931. J. PFOTZER SAFETY VALVE FOR BOILING VESSELS 2 Sheets-Shet 2 Filed Feb. 12, 1930 lnvenfom J Pf'o +36) Patented June 23, 1931 UNITED STATES JAKOBY rro'rznn, or xnnnf-nnnnn, GERMANY SAFETY VALVE FOR ,BOILING vnssnts Application filed February 12, 1930, Serial No.-427,893, and in Germany June 25, 1928.

This invention relates to a safety valve for boiling vessels, the contents of which cause the valve cone and the valve spindle to stick. Such boiling vessels are chiefly used for b011- 5, ing in the manufacture of cellulose. It has already been proposed, for preventing the grave danger resulting from the valve sticking, for instance, in the ordinary safety valve of steam boilers, which is forced down on to its seat by a weight acting through a valve spindle, to raise by means of an electrically operated lifting magnet the loading weight and the valve rod'together with the pressure member which is pivotally con- 1 nected to the latter. The valve itself, however, will remain on its seat if it has become stuck to it. In previous valve arrangements there is no certainty that, even when the loading weight is lifted, while the valve itself remains stuck, they will actually act in such a manner as to prevent all danger. The present invention overcomes this difficulty by causing the lifting force to act indirectly or directly on the valve itself for the purpose of releasing the valve.

In the accompanying drawings which show a constructional example of the present invention,

Figure 1 shows the safety Valve combined with a vessel for cooking cellulose in elevation and part section.

Figure 2 shows the safety valve alone, partly in longitudinal section and partly in elevation.

Figure 3 is a diagram of connections for the electric control of the safety valve.

Figure 4 shows a mechanical part of the controlling gear for the safety valve in vertical section, and

Figure 5 is a section on line AB of Figure 4.

The cooking vessel 2 which is fitted with a pressure gauge 1 is provided in the usual way with a safety valve 3, the valve member 4 of which is held down on its seat by means of the valve spindle 5, by the valve lever 6 and the loading weight 7 which is slidable thereon. The end of the valve lever 6 engages a lifting magnet 8, the energizing winding of which is connected by'the lead 9 (Figure 1) to the source of electric curi'entIO Fig. The pressure gauge 1 is a--so-called contact pressure gauge which is interposed in a circuit including the battery 10 and a relay 11 which latter controls the flow of current to the magnet 8.

When the contact pressure gauge 1 indicates 'the permissible pressure limit in the cooking vessel 2, the magnet 8 is energized and lifts not only the loading weight 7 1160 but also the valve lever 6 which is coupled to the valve spindle 5, so that the latter and the valve member *4 which is connected 'to it, are raised, the latter being drawn upwards or if it has become stuck, torn oif Yitsseat. For preventing the valve becomingstuck during the boiling operation, or ifthe apparatus is out of operation for a considerable period during which the valve '4is not raised, controlling means 12. (Figure 3) is interposed in the circuit of the magnet 8 whichenergizes the magnet 8 at suificiently short intervals to raise the valve 4 from its seat and allow it to drop again. In'order, however,-to-enable the whole valve arrange- *inent'to operatenormally' as a safety valve, the following arrangement is provided in accordance with Figures 4and 5.

The lifting magnet 8 is coupled not rigidly but loosely in thedirection of the lifting motion with the valve lever by the magnet stirmp 13 and the valve stirrup 14 (Figure 4). There is a further pivotal connection between a transmission lever 15 and a control bolt 16 which is rigidly connected to the magnet stirrup13. The connection is established over 'the iivotally connected straps 17, 18'and the intern'iediate pin 19. The pivot pins 20, 21 are guided in the narrow guiding slots 22 of the frame 23, whilethe "pivot 'pin.24 is arrangedso as to enter a widened guide .25. The'pivot pin 20 also supports the'transmi'ssion levers 15 which can rest on the stop pin 26 of the valve stirrup'14. V

If for any reason the lifting magnet should failto act,the pressure in the cooking vessel can, on the permissible maximum pressure being exceeded, lift the valve if it should not have stuck, the transmission lever 15 being raised by the stop 26 into the positions shown in broken lines in Figure 4:, as the straps 17 and 18 can collapse through the pin 24 moving laterally in the widened guide 25. Should the lifting magnet become operative again when the parts are in this position, the joint 21 will be raised in the guide 22 and the straps will move into their extended position. Should the circuit thereupon be interrupted, the magnet 8, will with its whole weight, force the valve lever 6 down through the intermediary of the transmission lever 15, during which motion the pins 20, 24:, 21 cannot come out of alignment owing to their being guided in the guide 22, this only being possible when the pin 24 reaches the point on of the widened guide 25. hen clockwork controlling means 12 are used, this sequence of operations is repeated at such short intervals that the valve and the valve spindle cannot become stuck. In principle the lifting force might instead of being applied electrically be applied, for in stance, by hydraulic or thermal means.

What I claim is:

1. A safety valve for boiling vessels, the contents of which are liable to cause the valve to stick to its seat, having a valve lover,

a weight on the said lever, an electric lifting magnet, a contact pressure gauge for controlling the lifting magnet, two loosely .interengaging stirrups capable of acting in the lifting direction of the magnet for coupling the lifting magnet and the valve lever,

one stirrup being attached to the movable part of the magnet and the other to the valve lever, two strap members pivoted together, a slotted guide for guiding the pivots of the said strap members, an intermediate member between the stirrups attached to the magnet and one of the strap members, stops on the stirrup attached to the valve lever and transmission levers attached to the free end of the other strap member for transmitting the weight of the lifting magnet by way of the said stop to the valve lever and the valve, as and for the purpose set forth.

2. A safety valve for boiling vessels, comprising a valve and a weighted lever thereon, an electric lifting magnet, a contact pressure gauge for controlling the lifting magnet, interengaging lever and magnet members to impart valve opening movement to the lever from the magnet, a pivoted link device connecting said members, and means carried by the lever member to move the link device to inoperative position during movement of the lever initiated by said valve.

In testimony whereof I have signed my name to this specification.

JAKOB PFOTZER. 

